Commitments and Contingencies Commitments And Contingencies (Narrative) (Details) (Details) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2016 USD ($) MW	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Entergy Arkansas [Member]
Regulatory Assets [Line Items]
Incremental NRC Inspection Costs	$ 19.6		$ 53.0
Entergy Arkansas [Member] | Subsequent Event [Member]
Regulatory Assets [Line Items]
Expected NRC inspection costs excluding remediation and response costs		$ 50.0
Entergy Wholesale Commodities [Member] | Pilgrim [Member]
Regulatory Assets [Line Items]
Incremental NRC Inspection Costs	5.0
Entergy Wholesale Commodities [Member] | Minimum [Member] | Pilgrim [Member]
Regulatory Assets [Line Items]
Expected NRC inspection costs	45.0
Entergy Wholesale Commodities [Member] | Maximum [Member] | Pilgrim [Member]
Regulatory Assets [Line Items]
Expected NRC inspection costs	$ 60.0
Entergy Wholesale Commodities [Member] | Subsequent Event [Member] | Pilgrim [Member]
Regulatory Assets [Line Items]
Expected NRC inspection costs		$ 30.0
Pilgrim [Member]
Regulatory Assets [Line Items]
Capacity Supply Obligations in ISO New England | MW	677